The present invention relates to a catheter system and, in particular, to a retention type catheter utilizing a balloon-type structure to keep the catheter within a patient's bladder. The present invention is especially directed to a catheter system which reduces the possibility of nosocomial urinary tract infections caused by or enhanced by insertion and retention of an endwelling catheter.
A major cause of in-hospital or nosocomial infections, especially those of the urinary tract, have been linked to endwelling catheters. Although typically less than 2% of those patients catheterized by a non-endwelling or non-retention type catheter eventually develop a urinary tract infection, a substantial number of those patients requiring an endwelling catheter do eventually have such an infection. In fact, for those patients having an endwelling catheter for three days or more, the likelihood of urinary tract infection is as high as 98%. Although the exact scientific principals are not completely understood, applicant presently believes that bacteria enter the urinary tract both as a result of insertion of the catheter tube through an unsterile urethral opening and through migration of bacteria by Brownian movement from the periuethral or perianal orifices while the catheter is within the bladder. The urine in the bladder makes and excellent media for reproduction of bacteria which enters thereinto. Typically, these bacteria are in the nature of 60% Escherichia colia of which a concentration in the order of 10,000 per milliliter of urine is considered an infection of the urinary tract. In fact, a single bacteriium may typically reproduce in an eight hour period to as many as 130,000 to 33,552,000 bacteria. Applicant believes that substantial complete voiding of urine from the bladder such that substantially no residual urine remains therein will significantly reduce the number of bacteria reproducing therein and thus will significantly reduce the incidence of bacterial infection within the urinary tract. During normal function of the bladder when no catheter is present therein, the normal voiding of urine by the body tends to flush out bacteria such that few if any remain within the bladder to continue reproduction. Therefore, it would appear important that this normal complete voiding of the bladder continue after a catheter is inserted therein, especially when the catheter is potentially bringing additional bacteria to the bladder when it is inserted.
A number of previous catheter devices of the retention type have been developed for the purpose of completing draining urine from the bladder. In particular, a number of these devices have apertures both below and above the balloon or in the balloon itself so as to attempt to completely drain the bladder cavity. Although such drainage techniques have resulted in reduced infection rates, where such catheters have been used, there is still an extremely high incidence or urinary tract infection even with such devices. It is applicant's belief that the high incidence of infection is indirectly attributable to the pliability and elasticity of the bladder itself. In particular, the bladder tends to collapse when empty, which collapse tends to occlude or block the drainage apertures communicating between the bladder and the interior lumen of the catheter. In addition, drainage of the bladder may create a slight suction which would also tend to pull or hold the interior wall or mucosa lining the bladder against the apertures so as to keep a small residual amount of urine from entering thereinto. The present invention, therefore, is designed to positively restrain the walls and mucosa of the bladder from at least a portion of the apertures communicating between the interior of the catheter and the bladder, while insuring that such apertures are situated or positioned such that they will drain a maximum amount of residual urine from the bladder.
Another problem associated with conventional catheters is related to the insertion tip thereof. The tip in order to effect proper insertion must be somewhat resilient and hard in nature. It is believed that this tip tends to rub against and thus bruise or irritate the bladder lining opposite the opening of the uretha into the bladder. Such irritation over a period of time may tend to remove protecting mucosa from the lining of the bladder and also tend to enhance possibility of infection where the tip rubs. Therefore, it is desired to position the tip relative to the balloon such that the wider and, thus, less penetrating portions of the balloon tend to urge the bladder walls away from the tip.
Yet another problem associated with conventional catheter systems is that the urine collection container or bag, as is usually used, tends to promote bacterial growth within the system. In particular, the conventional systems normally have a rather small container which must be emptied on a regular basis, normally in the nature of every eight hours. Every time the seal of the system is broken so as to empty the container, bacteria are free to enter thereinto. In addition, many containers have lower spigots which are easy for bacteria to settle around and allow such bacteria to enter into the system when opened. Also, the urine tends to, as was previously mentioned, be an excellent growth media so as to promote bacteria growth within the container. It is also noted that there is typically no or insufficient support means for the container, especially when the patient must travel such as in a wheelchair or the like, so that the container is often pulled across the floor whereupon the container accumulates additional bacterial contamination therefrom. Finally, the conventional urine containers are often reusable or are manufactured in such a manner that they may be easily reused by an attendant pouring the urine therefrom. Such reuse tends to promote growth of residual bacteria remaining from the previous usage. Therefore, a containment vessel is provided herein which will preferably have only one small restricted opening for allowing the urine to enter thereinto, which opening is sufficiently small enough such that an attendant would not want to take the time to try to remove the urine therefrom, and, thus, the vessel is substantially nonreusable. Preferably, the vessel is designed to hold urine from at least a 24 hour period, such that the system need not be broken more than once in a 24 hour period, thereby reducing chance of contamination and reducing labor. The vessel also has included therein a sufficient amount of bacteriacide suitable for killing any bacteria which would normally enter into the vessel within a 24 hour period. Preferably, such a bacteriacide would be of such a nature so as not to interfere with tests which may be run on the urine or produce an allergic type of reaction within the patient. The bacteriacide may be eliminated should same interfere with tests for a particular patent. In addition, a hanger is provided which is adapted for holding the containment vessel securely on the rail of a hospital bed or on a foot plate of a wheelchair so as to maintain the containment vessel in an upright position in either case. Preferably, a sampling port is provided within the catheter system such that a sterile needle may be inserted into the system so as to remove urine therefrom without inserting bacteria.